Thousands of asylum seekers from the Democratic Republic of the Congo have fled to Burundi in the past three days over fierce fighting in the eastern parts of the country, Burundi police say.

Nearly 7,000 Congolese have crossed Lake Tanganyika and taken refuge in Burundi since Wednesday as clashes raged between DR Congo government forces and rebels in the troubled eastern province of South Kivu.

Burundi police said on Friday a total of 6,692 refugees had registered in just three days to escape fighting between the army and the Yakutumba militia, although the flow appeared to have since slowed.

“Yesterday, Lake Tanganyika seemed to be completely covered by hundreds of boats of all sizes, packed with refugees and their property, it was quite sight,” one rights activist told AFP.

Congo’s President Joseph Kabila told a press conference that the security situation in the east, much of which is in the hands of rival militias, was “worrying.”

The UN refugee agency or the Burundian authorities have not made any immediate comment about the situation yet.

The Congolese government said last week it was waging “war” against two militias in the east, the Yakutumba and the Allied Democratic Force (ADF) rebel groups.

The Democratic Republic of the Congo had one of the most brutal colonial rules before undergoing decades of corrupt dictatorship and back-to-back civil wars that left the mineral-rich country poor and politically unstable.

Dozens of armed groups have been active in the eastern DR Congo, long after the official end of a 1998-2003 war during which millions of people died, mostly of hunger and disease.

The United Nations in January warned that the Democratic Republic of the Congo was at a “breaking point,” saying this year it will seek more than $1.5 billion to respond to the worsening humanitarian crisis in the country.

The UN this year will seek more than $1.5 billion to respond to the worsening humanitarian crisis in the Democratic Republic of Congo.

“The size of the crisis in the Congo is really challenging our collective ability to respond”, said the UN migration agency’s chief envoy to the country, Jean-Philippe Chauzy.

The escalating violence in Congo’s center and east this year comes amid a political crisis in the country due to President Kabila’s refusal to leave office after his term expired in December 2016.

In 2006, the UN mission helped carry out Congo’s first free and fair elections in 46 years, paving the way for President Joseph Kabila to be elected for a five-year term.

His second term in office ended in 2016. Under the DR Congo’s constitution, Kabila is banned from seeking a third term. However, Kabila is authorized to stay in office until his successor is elected but he decided to remain in power. This prompted the UN to urge the Congolese authorities “to respect the fundamental freedoms enshrined in the Congolese Constitution.”

The delay in holding an election has flared up violence in the country.